diff --git a/config/gmp_mpfr/mpfr.in b/config/gmp_mpfr/mpfr.in
index a54804c5..00818b83 100644
--- a/config/gmp_mpfr/mpfr.in
+++ b/config/gmp_mpfr/mpfr.in
@@ -12,6 +12,11 @@ config MPFR_V_2_3_2
     bool
     prompt "2.3.2"
 
+config MPFR_V_2_4_0
+    bool
+    prompt "2.4.0  (EXPERIMENTAL)"
+    depends on EXPERIMENTAL
+
 # CT_INSERT_VERSION_ABOVE
 # Don't remove above line!
 endchoice
@@ -20,6 +25,7 @@ config MPFR_VERSION
     string
     default "2.3.1" if MPFR_V_2_3_1
     default "2.3.2" if MPFR_V_2_3_2
+    default "2.4.0" if MPFR_V_2_4_0
 # CT_INSERT_VERSION_STRING_ABOVE
 # Don't remove above line!